ABSTRACT The number of women incarcerated in the United States has increased more than 600% over the past three decades; today more 200,000 women are behind bars. National estimates indicate that between 3-4% of incarcerated women are pregnant at the time they enter prison. Incarcerated pregnant women face disproportionately high risk relative to pregnant women in the general population. They are more likely to be poor, have lower levels of education, higher rates of trauma exposure in childhood and adulthood, higher rates of substance use, and more mental and physical health problems. These risks can compromise their health and the health of their infants. Given their increased prenatal risk and likelihood of obstetric complications, providing pregnant incarcerated women with doulas ? non-medical birth companions who provide individualized prenatal education and continuous labor support ? may improve maternal, fetal, and infant outcomes. We have previously described an innovative community-university-corrections partnership and demonstrated that doula support is a feasible intervention with incarcerated women. In descriptive analyses, we have demonstrated promising maternal and neonatal outcomes among incarcerated women who received doula support, including very low rates of cesarean deliveries and few preterm or low-birth weight infants. The proposed project will utilize a new data source to conduct a rigorous test of the efficacy and assess the cost- benefits of doula care for incarcerated pregnant women. The long-term goal of the proposed project is to create changes in the correctional health care system that promote the health of incarcerated pregnant women and their infants. Thus, the overall objective of this application is to test the efficacy and demonstrate the cost- effectiveness of one-on-one doula support for incarcerated women?s birth outcomes. Our central hypothesis is that incarcerated women who received doula support will have better birth outcomes, including higher rates of spontaneous vaginal deliveries, and lower rates of preterm and low birthweight infants, compared to incarcerated women who did not receive doula support. We also expect that the short-term benefits of doula care will outweigh the costs. We will accomplish this objective and evaluate our hypothesis by pursuing the two specific aims: 1) Compare the delivery and birth outcomes of incarcerated women who received doula support with incarcerated women who did not; 2) Conduct an economic evaluation of one prison doula project. Results from this study are expected to fundamentally advance our understanding of doula care as an innovative and cost-effective intervention that improves the health of pregnant incarcerated women and their infants. Demonstrating the efficacy and cost-effectiveness of this intervention will advance a multi-site implementation trial of doula support for women incarcerated in other correctional facilities across the country.